Path management techniques for storage networks

ABSTRACT

Improved path management techniques for storage networks are described. In one embodiment, for example, an apparatus may comprise a processor circuit, a detection component for execution by the processor circuit to receive an advertisement of a set of paths for accessing a logical storage volume and determine whether the set of paths comprises an optimized path, and a modification component for execution by the processor circuit to, when the set of paths does not comprise an optimized path, send a first instruction to update a reporting nodes parameter for the logical storage volume to identify an owner node for the logical storage volume and a corresponding partner node. Other embodiments are described and claimed.

RELATED CASE

This application claims priority to U.S. Provisional Patent Application No. 61/916,102, filed Dec. 13, 2013, the entirety of which is hereby incorporated by reference.

BACKGROUND

In a storage network such as a storage area network (SAN) cluster, abstraction techniques may be utilized in order to present physical storage locations of a plurality of storage nodes as a single virtual storage array. Such abstraction techniques may involve defining various logical interfaces that correspond to various physical ports of the storage nodes and presenting the logical interfaces to hosts as paths via which to access logical storage volumes of the virtual storage array. In some cases, the hosts that utilize the virtual storage array may be capable of properly handling only a limited number of paths to each logical storage volume. Under such circumstances, a management entity for the virtual storage array may select particular paths for use by any given host group to access a logical storage volume, and may advertise the availability of the logical storage volume via the selected paths. In order to increase the efficiency with which hosts may access logical storage volumes, it may be desirable for hosts to be capable of instructing the management entity to modify the advertised paths when they do not include an optimized access path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of a first operating environment.

FIG. 2 illustrates one embodiment of a second operating environment.

FIG. 3 illustrates one embodiment of an apparatus and one embodiment of a first system.

FIG. 4 illustrates one embodiment of a logic flow.

FIG. 5 illustrates one embodiment of a storage medium.

FIG. 6 illustrates one embodiment of a computing architecture.

FIG. 7 illustrates one embodiment of a communications architecture.

DETAILED DESCRIPTION

Various embodiments may be generally directed to improved path management techniques for storage networks. In one embodiment, for example, an apparatus may comprise a processor circuit, a detection component for execution by the processor circuit to receive an advertisement of a set of paths for accessing a logical storage volume and determine whether the set of paths comprises an optimized path, and a modification component for execution by the processor circuit to, when the set of paths does not comprise an optimized path, send a first instruction to update a reporting nodes parameter for the logical storage volume to identify an owner node for the logical storage volume and a corresponding partner node. Other embodiments are described and claimed.

Various embodiments may comprise one or more elements. An element may comprise any structure arranged to perform certain operations. Each element may be implemented as hardware, software, or any combination thereof, as desired for a given set of design parameters or performance constraints. Although an embodiment may be described with a limited number of elements in a certain topology by way of example, the embodiment may include more or less elements in alternate topologies as desired for a given implementation. It is worthy to note that any reference to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrases “in one embodiment,” “in some embodiments,” and “in various embodiments” in various places in the specification are not necessarily all referring to the same embodiment.

FIG. 1 illustrates an embodiment of an operating environment 100 such as may be associated with various embodiments. As shown in FIG. 1, in operating environment 100, hosts 102-1, 102-2, and 102-3 are communicatively coupled to a virtual storage array 104. Virtual storage array 104 may comprise a network storage system that is controlled and/or managed by an management entity 106 in order to provide one or more logical storage volumes 108 for use by hosts 102-1, 102-2, and 102-3. More particularly, management entity 106 may be operative to implement virtual storage array 104 by applying various layers and/or types of abstraction to an underlying network of physical storage nodes and associated ports. For example, management entity 106 may be operative to implement virtual storage array 104 by abstracting the physical storage nodes and associated ports of a storage area network (SAN) cluster.

As shown in FIG. 1, hosts 102-1, 102-2, and 102-3 may access virtual storage array 104 through various logical interfaces (LIFs) 110, via a switch 112. In some embodiments, the various LIFs 110 may correspond to various ports residing at various network storage nodes. In various embodiments, for example, the various LIFs 110 may correspond to various small computer system interface (SCSI) ports of various storage nodes, and thus may correspond to various SCSI paths. In some embodiments, because of the abstraction provided by management entity 106, the localities of LIFs 110 may be opaque to hosts 102. However, in various embodiments, beneath the abstraction implemented by management entity 106, there may be various considerations that render particular LIFs 110 more suitable than others for use as paths to access particular logical storage volumes 108.

FIG. 2 illustrates an embodiment of an operating environment 200 that comprises an example of such a scenario. As shown in FIG. 2, virtual storage array 204 comprises a physical arrangement of storage nodes 214 and various interconnections, which is abstracted by management entity 206 in order to present virtual storage array 204 to various hosts 202. The various storage nodes 214 are arranged in high-availability pairs, each of which comprises two storage nodes 214 connected by a private heartbeat connection 216. Additionally, all of the storage nodes 214 are interconnected by a cluster interconnect 218. The various LIFs 210 in FIG. 2 comprise abstractions of physical ports associated with the various storage nodes 214. For example, LIF0 comprises an abstraction of a physical port associated with storage node 214-1. It is worthy of note that although management entity 206 is depicted as being external to the various storage nodes 216 of virtual storage array 204 in FIG. 2, the embodiments are not so limited. For example, in some embodiments, one or more of the storage nodes 216 may act as management entity 206. The embodiments are not limited in this context.

In various embodiments, due to the locality characteristics of LIFs 210 and/or logical storage volumes 208, particular LIFs 210 may be more or less optimal than others for use in accessing particular logical storage volumes 208. For example, in FIG. 2, LIF0 may comprise an optimized path to logical storage volume 208-1, because it corresponds to a port on storage node 214-1, which is the same storage node as that containing the physical storage locations to which logical storage volume 208-1 corresponds. In contrast, LIF5 may correspond to a port on storage node 214-6, and may thus require the use of cluster interconnect 218 to reach logical storage volume 208-1 at storage node 214-1. There may be added latency associated with communicating over cluster interconnect 218, and as such, LIF5 may comprise an unoptimized path. The embodiments are not limited in this context.

In some embodiments, management entity 206 may be operative to define various groups of hosts 202 and to map various logical storage volumes 208 to various such groups in order to grant them access to those logical storage volumes 208. For example, in FIG. 2, management entity 206 may be operative to define a host group 220 that comprises hosts 202-1 and 202-2, and may map logical storage volume 208-1 to the host group 220 such that hosts 202-1 and 202-2 are able to access logical storage volume 208-1. The embodiments are not limited to this example.

In various embodiments, it may be necessary and/or desirable to limit the number of LIFs 210 that are presented to each host 202 for accessing any particular logical storage volume 208. In some embodiments, each host 202 may be capable of properly handling up to a particular number of paths to any particular logical storage volume 208. For example, in FIG. 2, hosts 202-1 and 202-2 may each be capable of properly handling up to four paths to logical storage volume 208-1. Since there are a total of six LIFs 210 via which logical storage volume 208-1 may be accessed in FIG. 2, it may be desirable for management entity to restrict hosts 202-1 and 202-2 to a subset of no more than four LIFs 210 for use in accessing logical storage volume 208-1. The embodiments are not limited to this example.

In various embodiments, management entity 206 may be capable of restricting the LIFs 210 presented to various hosts 202 using portsets, each of which may comprise a configuration object identifying a set of LIFs 210. In some embodiments, management entity 206 may be capable of binding any particular portset to a host group, such that the hosts 202 of that host group are presented only with the LIFs 210 identified by the portset. For example, in FIG. 2, management entity 206 may be capable of generating a portset that identifies LIF0, LIF1, LIF4, and LIF5, and may be capable of binding that portset to host group 220 such that hosts 202-1 and 202-2 are presented only with LIF0, LIF1, LIF4, and LIF5. The embodiments are not limited to this example.

In various embodiments, when management entity 206 binds a portset to a host group, the hosts 202 of the host group may be restricted to the defined group of LIFs 210 with respect to access to all logical storage volumes 208 to which they have been granted access. In an example, management entity 206 may grant host group 220 access to logical storage volumes 208-1, 208-2, and 208-4 and may then use a portset to restrict host group 220 to using LIF0, LIF1, LIF4, and LIF5. In this example, hosts 202-1 and 202-2 may thus be restricted to this set of four LIFs 210 for use as access paths to logical storage volume 208-1 and also restricted to this set of four LIFs 210 for use as access paths to logical storage volumes 208-2 and 208-4. The embodiments are not limited to this example.

In some embodiments, hosts 202 may have one or more mechanisms at their disposal for differentiating between available LIFs 210 based on their suitability for accessing particular logical storage volumes 208. In various embodiments, for example, hosts 202 may utilize asymmetrical logical unit access (ALUA) procedure to classify available LIFs 210 as being optimized or unoptimized with respect to particular logical storage volumes 208. According to the ALUA procedure, each available LIF 210 that corresponds to a port at an owner node for a given logical storage volume 208 may be categorized as active/optimized with respect to that logical storage volume 208, and each available LIF 210 that corresponds to a port at another node may be categorized as active/unoptimized. Continuing with the above example in which host group 220 is restricted to using LIF0, LIF1, LIF4, and LIF5, hosts 202-1 and 202-2 may each use an ALUA procedure to identify LIF1 as an active/optimized path with respect to logical storage volume 208-2 and to identify each of LIF0, LIF4, and LIF5 as an active/unoptimized path with respect to logical storage volume 208-2. The embodiments are not limited to this example

One drawback associated with the use of portsets to observe access path limits of hosts 202 may be that when mobility events occur, some hosts 202 may be left with only unoptimized paths to particular logical storage volumes 208. A mobility event may involve a logical storage volume 208 corresponding to physical storage at one storage node 214 being reassigned to correspond instead to physical storage at a different storage node 214. FIG. 2 depicts an example of a mobility event 222, according to which logical storage volume 208-1 may be reassigned from storage node 214-1 to storage node 214-3. In this example, if management entity 206 has defined a portset to restrict host group 220 to using LIF0, LIF1, LIF4, and LIF5, then all of the available paths from host 202-1 and 202-2 to logical storage volume 208-1 will become unoptimized paths. The embodiments are not limited to this example.

In some embodiments, it may be possible to modify a portset in order to provide host group 220 with an optimized path to a relocated logical storage volume 208. For example, in FIG. 2, it may be possible to modify the portset for host group 220 such that hosts 202-1 and 202-2 are able to access the moved storage volume on LIF2, which may be an optimized path to logical storage volume 208-1 following mobility event 222. However, in various embodiments, the procedure for modifying the portset may not be automatic, but rather may require manual steps in order for the relocated logical storage volume 208-1 to be discoverable through LIF2. Furthermore, since the path restrictions of the portset may apply to all logical storage volumes 208 to which the host group 220 has access, modifying the portset to create an optimized path to one logical storage volume 208 may leave the host group 220 with no optimized path to another logical storage volume 208. For example, if management entity 206 substitutes LIF2 and LIF3 for LIF0 and LIFT in the portset for host group 220, hosts 202-1 and 202-2 may be provided with an optimized path to logical storage volume 208-1 following mobility event 222, but may no longer have an optimized path to logical storage volume 208-2. The embodiments are not limited to this example.

Disclosed herein are improved path management techniques for storage networks such as that depicted in operating environment 200 of FIG. 2. According to such improved techniques, the storage nodes via which a given host group may access a particular logical storage volume may be specified by a reporting nodes parameter in a configuration object that maps that logical storage volume to that host group. When a host detects that it has been left without an optimized path to a logical storage volume, it may send an instruction to a management entity to modify the reporting nodes parameter such that the logical storage volume is accessible via LIFs of its new owner node and corresponding partner node(s). The management entity may add the new owner node and partner node(s) to the reporting nodes parameter, and the host may then perform a scan to discover newly available paths associated with the new owner node and partner node(s). The embodiments are not limited in this context.

FIG. 3 illustrates a block diagram of an apparatus 300 such as may implement improved path management techniques. Apparatus 300 may comprise an example of a host 202 of FIG. 2 according to some embodiments. As shown in FIG. 3, apparatus 300 comprises multiple elements including a processor circuit 302, a memory unit 304, and a path management module 306. The embodiments, however, are not limited to the type, number, or arrangement of elements shown in this figure.

In various embodiments, apparatus 300 may comprise processor circuit 302. Processor circuit 302 may be implemented using any processor or logic device, such as a complex instruction set computer (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, an x86 instruction set compatible processor, a processor implementing a combination of instruction sets, a multi-core processor such as a dual-core processor or dual-core mobile processor, or any other microprocessor or central processing unit (CPU). Processor circuit 302 may also be implemented as a dedicated processor, such as a controller, a microcontroller, an embedded processor, a chip multiprocessor (CMP), a co-processor, a digital signal processor (DSP), a network processor, a media processor, an input/output (I/O) processor, a media access control (MAC) processor, a radio baseband processor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device (PLD), and so forth. The embodiments are not limited in this context.

In some embodiments, apparatus 300 may comprise or be arranged to communicatively couple with a memory unit 304. Memory unit 304 may be implemented using any machine-readable or computer-readable media capable of storing data, including both volatile and non-volatile memory. For example, memory unit 304 may include read-only memory (ROM), random-access memory (RAM), dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), synchronous DRAM (SDRAM), static RAM (SRAM), programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, polymer memory such as ferroelectric polymer memory, ovonic memory, phase change or ferroelectric memory, silicon-oxide-nitride-oxide-silicon (SONOS) memory, magnetic or optical cards, or any other type of media suitable for storing information. It is worthy of note that some portion or all of memory unit 304 may be included on the same integrated circuit as processor circuit 302, or alternatively some portion or all of memory unit 304 may be disposed on an integrated circuit or other medium, for example a hard disk drive, that is external to the integrated circuit of processor circuit 302. Although memory unit 304 is comprised within apparatus 300 in FIG. 3, memory unit 304 may be external to apparatus 300 in some embodiments. The embodiments are not limited in this context.

In various embodiments, apparatus 300 may comprise a path management module 306. Path management module 306 may comprise logic, circuitry, and/or instructions operative to manage the paths via which apparatus 300 may access logical storage of a storage network 350. In some embodiments, path management module 306 may be operative to manage such paths such that apparatus 300 is provided with an optimized access path to the logical storage. The embodiments are not limited in this context.

FIG. 3 also illustrates a block diagram of a system 340. System 340 may comprise any of the aforementioned elements of apparatus 300. System 340 may further comprise a display 345. Display 345 may comprise any display device capable of displaying information received from processor circuit 302. Examples for display 345 may include a television, a monitor, a projector, and a computer screen. In one embodiment, for example, display 345 may be implemented by a liquid crystal display (LCD), light emitting diode (LED) or other type of suitable visual interface. Display 345 may comprise, for example, a touch-sensitive display screen (“touchscreen”). In various implementations, display 345 may comprise one or more thin-film transistors (TFT) LCD including embedded transistors. The embodiments, however, are not limited to these examples.

In general operation, apparatus 300 and/or system 340 may be operative to access a logical storage volume 308 of a logical storage array implemented by a management entity 360 for the storage network 350. In various embodiments, the management entity 360 may be operative to define the logical storage volume 308 as an abstraction of physical storage locations of the storage network 350. As such, in some embodiments, there may be an underlying locality associated with the logical storage volume 308. In various embodiments, management entity 360 may be operative to assign a logical unit number (LUN) 310 to the logical storage volume 308. In some embodiments, the LUN 310 may uniquely identify the logical storage volume 308 within the context of the virtual storage array. The embodiments are not limited in this context.

In various embodiments, management entity 360 may be operative to generate a host group object 312. Host group object 312 may comprise information identifying a set of hosts, which may be referred to as a host group. In some embodiments, in order to enable the host group identified by host group object 312 to access the logical storage volume 308, management entity 360 may be operative to generate a LUN map 314. In various embodiments, LUN map 314 may comprise a configuration object for logical storage volume 308. In some embodiments, LUN map 314 may comprise the LUN 310 and a host group identifier (ID) 316 that identifies the host group defined by host group object 312, and may indicate that that host group is to be granted access to the logical storage volume 308 identified by the LUN 310. In various embodiments, the host group defined by host group object 312 may include apparatus 300 and/or system 340, and thus LUN map 314 may indicate that apparatus 300 and/or system 340 is to be granted access to the logical storage volume 308 identified by the LUN 310. The embodiments are not limited in this context.

In some embodiments, management entity 360 may be operative to send a LUN advertisement 320 to apparatus 300 and/or system 340. LUN advertisement 320 may comprise information indicating that logical storage volume 308 is available using the LUN 310 identified in LUN map 314. In various embodiments, LUN advertisement 320 may comprise available path information 322. Available path information 322 may comprise information identifying a set of LIFs via which apparatus 300 and/or system 340 may access logical storage volume 308. The embodiments are not limited in this context.

In some embodiments, management entity 360 may be operative to implement an access management scheme according to which optimal paths are maintained for use by host groups to access logical storage volumes of a virtual storage array. In various embodiments, according to such an access management scheme, management entity 360 may be operative to generate LUN map 314 such that it includes a reporting nodes parameter 324. Reporting nodes parameter 324 may comprise information identifying one or more storage nodes of the storage network 350. In some embodiments, according to the access management scheme, only LIFs corresponding to storage nodes identified by the reporting nodes parameter 324 in LUN map 314 may be advertised to the host group identified by the host group ID 316 in LUN map 314. In various embodiments, management entity 360 may be operative to determine available path information 322 based on reporting nodes parameter 324, such that available path information 322 identifies such LIFs. The embodiments are not limited in this context.

In some embodiments, in order to support the provision of optimized access paths to hosts accessing storage network 350, the access management scheme may include a convention according to which each logical storage volume is to be reported only out of the LIFs associated with its owner node and the partner node(s) for its owner node. For example, with respect to FIG. 2, the convention may stipulate that logical storage volume 208-4 is to be reported only out of the LIF4 associated with its owner node 214-5 and the LIF5 associated with the corresponding partner node 214-6. Returning to FIG. 3, in various embodiments, whether available path information 322 identifies an optimized path for accessing logical storage volume 308 may depend on whether reporting nodes parameter 324 properly identifies a current owner node and corresponding partner node(s) for logical storage volume 308. If reporting nodes parameter 324 does not properly identify such nodes, then management entity 360 may be operative to generate a LUN advertisement 320 comprising available path information 322 that identifies only unoptimized paths. The embodiments are not limited in this context.

An example of such a scenario in some embodiments may involve a mobility event. When a mobility event occurs and logical storage volume 308 is moved to a different storage node, reporting nodes parameter 324 may not properly identify the new owner node and corresponding partner node(s) for logical storage volume 308. For example, following mobility event 222 in FIG. 2, reporting nodes parameter 324 may not properly identify the new owner node 214-3 and corresponding partner node 214-4 for logical storage volume 208-1. As a result, management entity 360 may advertise only unoptimized paths to the relocated logical storage volume 208-1. The embodiments are not limited to this example.

In various embodiments, path management module 306 of FIG. 3 may comprise a detection component 326. Detection component 326 may comprise logic, circuitry, and/or instructions operative to detect whether the available path information 322 in LUN advertisement 320 identifies only unoptimized paths. Hereinafter, the term “unoptimized LUN advertisement” shall be employed to denote a LUN advertisement in which the available path information 322 identifies only unoptimized paths. In some embodiments, detection component 326 may be operative to perform this detection based on information provided by management entity 360 and/or external logic and/or circuitry in conjunction with the provision of LUN advertisement 320. For example, in various embodiments, management entity 360 may comprise a small computer system interface (SCSI) target and may provide apparatus 300 and/or system 340 with information describing asymmetrical logical unit access (ALUA) states of each advertised path. In such embodiments, the ALUA state for each path may indicate whether that path comprised an optimized path or an unoptimized path. Detection component 326 may then be operative to detect whether LUN advertisement 320 is unoptimized based on the provided ALUA states. The embodiments are not limited to this example.

In some embodiments, path management module 306 may comprise a modification component 328. Modification component 328 may comprise logic, circuitry, and/or instructions operative to generate instructions for forwarding to management entity 360 in order to secure an optimized path for accessing logical storage volume 308.

In various embodiments, when detection component 326 detects an unoptimized LUN advertisement 320, modification component 328 may be operative to send an add node instruction 330 to management entity 360. Add node instruction 330 may comprise information identifying a current owner node and corresponding partner node(s) for logical storage volume 308, and instructing management entity 360 to add those identified nodes to reporting nodes parameter 324. In some embodiments, add node instruction 330 may comprise a command line interface (CLI) command. In various other embodiments, add node instruction 330 may comprise an application programming interface (API) operation. In some embodiments, upon receipt of add node instruction 330, management entity 360 may be operative to update reporting nodes parameter 324 and generate a new LUN advertisement 320. The embodiments are not limited in this context.

In various embodiments, after modification component 328 sends the add node instruction 330 to management entity 360, detection component 326 may be operative to detect the new LUN advertisement 320 sent by management entity 360. In some embodiments, detection component 326 may be operative to detect the new LUN advertisement 320 by scanning a SCSI bus. In various embodiments, detection component 326 may be operative to determine one or more newly added paths identified in the available path information 322 of the new LUN advertisement 320, and to confirm that apparatus 300 and/or system 340 has been provided with an optimized path. In some embodiments, modification component 328 may be operative to update a multi-path input/output (MPIO) stack based on the newly added paths determined by detection component 326. The embodiments are not limited in this context.

In various embodiments, once detection component 326 has confirmed that apparatus 300 and/or system 340 has been provided with an optimized path, modification component 328 may be operative to send a remove node instruction 332 to management entity 360. Remove node instruction 332 may comprise information identifying one or more nodes that management entity 360 is to remove from reporting nodes parameter 324. In some embodiments, for example, remove node instruction 332 may indicate that management entity 360 should remove all nodes other than the new owner node and corresponding partner node(s) from reporting nodes parameter 324. In various embodiments, remove node instruction 332 may comprise a CLI command. In some other embodiments, remove node instruction 332 may comprise an API operation. In an example embodiment, remove node instruction 332 may indicate that management entity 360 should remove a previous owner node and previous corresponding partner node(s) from reporting nodes parameter 324. The embodiments are not limited to this example.

In various embodiments, path management module 306 may be capable of configuring optimal paths in advance for mobility events of which it has control and/or advance knowledge. For example, in some embodiments, logic on apparatus 300 and/or system 340 may elect to initiate a mobility event for logical storage volume 308, and may inform path management module 306 of the identities of the post-mobility owner node and corresponding partner node(s) in advance. In various such embodiments, modification component 328 may then be operative to send an appropriate add node instruction 330 to management entity 360 prior to the mobility event, such that an optimized path to the relocated logical storage volume 308 exists immediately following the mobility event. The embodiments are not limited in this context.

Operations for the above embodiments may be further described with reference to the following figures and accompanying examples. Some of the figures may include a logic flow. Although such figures presented herein may include a particular logic flow, it can be appreciated that the logic flow merely provides an example of how the general functionality as described herein can be implemented. Further, the given logic flow does not necessarily have to be executed in the order presented unless otherwise indicated. In addition, the given logic flow may be implemented by a hardware element, a software element executed by a processor, or any combination thereof. The embodiments are not limited in this context.

FIG. 4 illustrates one embodiment of a logic flow 400, which may be representative of the operations executed by one or more embodiments described herein. As shown in logic flow 400, an advertisement of a set of paths for accessing a logical storage volume may be received at 402. For example, path management module 306 of FIG. 3 may be operative to receive a LUN advertisement 320 comprising available path information 322 that identifies a set of paths for accessing logical storage volume 308. At 404, it may be determined whether the set of paths comprises an optimized path. For example, detection component 326 of FIG. 3 may be operative to determine whether a set of paths identified by available path information 322 comprises an optimized path. In some embodiments, an ALUA state of each path may be used to determine whether that path comprises an optimized path. At 406, when the set of paths does not comprise an optimized path, an instruction may be sent to update a reporting nodes parameter for the logical storage volume to identify an owner node and corresponding partner node(s) for the logical storage volume. For example, modification component 328 of FIG. 3 may be operative to send an add node instruction 330 to management entity 360, and the add node instruction 330 may indicate that reporting nodes parameter 324 should be updated such that it identifies an owner node for logical storage volume 308 and one or more corresponding partner nodes. The embodiments are not limited to these examples.

FIG. 5 illustrates an embodiment of a storage medium 500. Storage medium 500 may comprise any non-transitory computer-readable storage medium or machine-readable storage medium, such as an optical, magnetic or semiconductor storage medium. In various embodiments, storage medium 500 may comprise an article of manufacture. In some embodiments, storage medium 500 may store computer-executable instructions, such as computer-executable instructions to implement logic flow 400 of FIG. 4. Examples of a computer-readable storage medium or machine-readable storage medium may include any tangible media capable of storing electronic data, including volatile memory or non-volatile memory, removable or non-removable memory, erasable or non-erasable memory, writeable or re-writeable memory, and so forth. Examples of computer-executable instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, object-oriented code, visual code, and the like. The embodiments are not limited in this context.

FIG. 6 illustrates an embodiment of an exemplary computing architecture 600 suitable for implementing various embodiments as previously described. In various embodiments, the computing architecture 600 may comprise or be implemented as part of an electronic device. In some embodiments, the computing architecture 600 may be used, for example, to implement apparatus 300 and/or system 340 of FIG. 3, logic flow 400 of FIG. 4, and/or storage medium 500 of FIG. 5. The embodiments are not limited in this context.

As used in this application, the terms “system” and “component” and “module” are intended to refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software in execution, examples of which are provided by the exemplary computing architecture 600. For example, a component can be, but is not limited to being, a process running on a processor, a processor, a hard disk drive, multiple storage drives (of optical and/or magnetic storage medium), an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a server and the server can be a component. One or more components can reside within a process and/or thread of execution, and a component can be localized on one computer and/or distributed between two or more computers. Further, components may be communicatively coupled to each other by various types of communications media to coordinate operations. The coordination may involve the uni-directional or bi-directional exchange of information. For instance, the components may communicate information in the form of signals communicated over the communications media. The information can be implemented as signals allocated to various signal lines. In such allocations, each message is a signal. Further embodiments, however, may alternatively employ data messages. Such data messages may be sent across various connections. Exemplary connections include parallel interfaces, serial interfaces, and bus interfaces.

The computing architecture 600 includes various common computing elements, such as one or more processors, multi-core processors, co-processors, memory units, chipsets, controllers, peripherals, interfaces, oscillators, timing devices, video cards, audio cards, multimedia input/output (I/O) components, power supplies, and so forth. The embodiments, however, are not limited to implementation by the computing architecture 600.

As shown in FIG. 6, the computing architecture 600 comprises a processing unit 604, a system memory 606 and a system bus 608. The processing unit 604 can be any of various commercially available processors, including without limitation an AMD®, Athlon®, Duron® and Opteron® processors; ARM® application, embedded and secure processors; IBM® and Motorola® DragonBall® and PowerPC® processors; IBM and Sony® Cell processors; Intel® Celeron®, Core (2) Duo®, Itanium®, Pentium®, Xeon®, and XScale® processors; and similar processors. Dual microprocessors, multi-core processors, and other multi-processor architectures may also be employed as the processing unit 604.

The system bus 608 provides an interface for system components including, but not limited to, the system memory 606 to the processing unit 604. The system bus 608 can be any of several types of bus structure that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and a local bus using any of a variety of commercially available bus architectures. Interface adapters may connect to the system bus 608 via a slot architecture. Example slot architectures may include without limitation Accelerated Graphics Port (AGP), Card Bus, (Extended) Industry Standard Architecture ((E)ISA), Micro Channel Architecture (MCA), NuBus, Peripheral Component Interconnect (Extended) (PCI(X)), PCI Express, Personal Computer Memory Card International Association (PCMCIA), and the like.

The system memory 606 may include various types of computer-readable storage media in the form of one or more higher speed memory units, such as read-only memory (ROM), random-access memory (RAM), dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), synchronous DRAM (SDRAM), static RAM (SRAM), programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, polymer memory such as ferroelectric polymer memory, ovonic memory, phase change or ferroelectric memory, silicon-oxide-nitride-oxide-silicon (SONOS) memory, magnetic or optical cards, an array of devices such as Redundant Array of Independent Disks (RAID) drives, solid state memory devices (e.g., USB memory, solid state drives (SSD) and any other type of storage media suitable for storing information. In the illustrated embodiment shown in FIG. 6, the system memory 606 can include non-volatile memory 610 and/or volatile memory 612. A basic input/output system (BIOS) can be stored in the non-volatile memory 610.

The computer 602 may include various types of computer-readable storage media in the form of one or more lower speed memory units, including an internal (or external) hard disk drive (HDD) 614, a magnetic floppy disk drive (FDD) 616 to read from or write to a removable magnetic disk 618, and an optical disk drive 620 to read from or write to a removable optical disk 622 (e.g., a CD-ROM or DVD). The HDD 614, FDD 616 and optical disk drive 620 can be connected to the system bus 608 by a HDD interface 624, an FDD interface 626 and an optical drive interface 628, respectively. The HDD interface 624 for external drive implementations can include at least one or both of Universal Serial Bus (USB) and IEEE 1394 interface technologies.

The drives and associated computer-readable media provide volatile and/or nonvolatile storage of data, data structures, computer-executable instructions, and so forth. For example, a number of program modules can be stored in the drives and memory units 610, 612, including an operating system 630, one or more application programs 632, other program modules 634, and program data 636. In one embodiment, the one or more application programs 632, other program modules 634, and program data 636 can include, for example, the various applications and/or components of the apparatus 300.

A user can enter commands and information into the computer 602 through one or more wire/wireless input devices, for example, a keyboard 638 and a pointing device, such as a mouse 640. Other input devices may include microphones, infra-red (IR) remote controls, radio-frequency (RF) remote controls, game pads, stylus pens, card readers, dongles, finger print readers, gloves, graphics tablets, joysticks, keyboards, retina readers, touch screens (e.g., capacitive, resistive, etc.), trackballs, trackpads, sensors, styluses, and the like. These and other input devices are often connected to the processing unit 604 through an input device interface 642 that is coupled to the system bus 608, but can be connected by other interfaces such as a parallel port, IEEE 1394 serial port, a game port, a USB port, an IR interface, and so forth.

A monitor 644 or other type of display device is also connected to the system bus 608 via an interface, such as a video adaptor 646. The monitor 644 may be internal or external to the computer 602. In addition to the monitor 644, a computer typically includes other peripheral output devices, such as speakers, printers, and so forth.

The computer 602 may operate in a networked environment using logical connections via wire and/or wireless communications to one or more remote computers, such as a remote computer 648. The remote computer 648 can be a workstation, a server computer, a router, a personal computer, portable computer, microprocessor-based entertainment appliance, a peer device or other common network node, and typically includes many or all of the elements described relative to the computer 602, although, for purposes of brevity, only a memory/storage device 650 is illustrated. The logical connections depicted include wire/wireless connectivity to a local area network (LAN) 652 and/or larger networks, for example, a wide area network (WAN) 654. Such LAN and WAN networking environments are commonplace in offices and companies, and facilitate enterprise-wide computer networks, such as intranets, all of which may connect to a global communications network, for example, the Internet.

When used in a LAN networking environment, the computer 602 is connected to the LAN 652 through a wire and/or wireless communication network interface or adaptor 656. The adaptor 656 can facilitate wire and/or wireless communications to the LAN 652, which may also include a wireless access point disposed thereon for communicating with the wireless functionality of the adaptor 656.

When used in a WAN networking environment, the computer 602 can include a modem 658, or is connected to a communications server on the WAN 654, or has other means for establishing communications over the WAN 654, such as by way of the Internet. The modem 658, which can be internal or external and a wire and/or wireless device, connects to the system bus 608 via the input device interface 642. In a networked environment, program modules depicted relative to the computer 602, or portions thereof, can be stored in the remote memory/storage device 650. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers can be used.

The computer 602 is operable to communicate with wire and wireless devices or entities using the IEEE 802 family of standards, such as wireless devices operatively disposed in wireless communication (e.g., IEEE 802.16 over-the-air modulation techniques). This includes at least Wi-Fi (or Wireless Fidelity), WiMax, and Bluetooth™ wireless technologies, among others. Thus, the communication can be a predefined structure as with a conventional network or simply an ad hoc communication between at least two devices. Wi-Fi networks use radio technologies called IEEE 802.11x (a, b, g, n, etc.) to provide secure, reliable, fast wireless connectivity. A Wi-Fi network can be used to connect computers to each other, to the Internet, and to wire networks (which use IEEE 802.3-related media and functions).

FIG. 7 illustrates a block diagram of an exemplary communications architecture 700 suitable for implementing various embodiments as previously described. The communications architecture 700 includes various common communications elements, such as a transmitter, receiver, transceiver, radio, network interface, baseband processor, antenna, amplifiers, filters, power supplies, and so forth. The embodiments, however, are not limited to implementation by the communications architecture 700.

As shown in FIG. 7, the communications architecture 700 comprises includes one or more clients 702 and servers 704. The clients 702 and the servers 704 are operatively connected to one or more respective client data stores 708 and server data stores 710 that can be employed to store information local to the respective clients 702 and servers 704, such as cookies and/or associated contextual information. Any one of clients 702 and/or servers 704 may implement apparatus 300 and/or system 340 of FIG. 3, logic flow 400 of FIG. 4, and/or storage medium 500 of FIG. 5 in conjunction with storage of information on any of client data stores 708 and/or server data stores 710.

The clients 702 and the servers 704 may communicate information between each other using a communication framework 706. The communications framework 706 may implement any well-known communications techniques and protocols. The communications framework 706 may be implemented as a packet-switched network (e.g., public networks such as the Internet, private networks such as an enterprise intranet, and so forth), a circuit-switched network (e.g., the public switched telephone network), or a combination of a packet-switched network and a circuit-switched network (with suitable gateways and translators).

The communications framework 706 may implement various network interfaces arranged to accept, communicate, and connect to a communications network. A network interface may be regarded as a specialized form of an input output interface. Network interfaces may employ connection protocols including without limitation direct connect, Ethernet (e.g., thick, thin, twisted pair 10/100/1000 Base T, and the like), token ring, wireless network interfaces, cellular network interfaces, IEEE 802.11a-x network interfaces, IEEE 802.16 network interfaces, IEEE 802.20 network interfaces, and the like. Further, multiple network interfaces may be used to engage with various communications network types. For example, multiple network interfaces may be employed to allow for the communication over broadcast, multicast, and unicast networks. Should processing requirements dictate a greater amount speed and capacity, distributed network controller architectures may similarly be employed to pool, load balance, and otherwise increase the communicative bandwidth required by clients 702 and the servers 704. A communications network may be any one and the combination of wired and/or wireless networks including without limitation a direct interconnection, a secured custom connection, a private network (e.g., an enterprise intranet), a public network (e.g., the Internet), a Personal Area Network (PAN), a Local Area Network (LAN), a Metropolitan Area Network (MAN), an Operating Missions as Nodes on the Internet (OMNI), a Wide Area Network (WAN), a wireless network, a cellular network, and other communications networks.

Various embodiments may be implemented using hardware elements, software elements, or a combination of both. Examples of hardware elements may include processors, microprocessors, circuits, circuit elements (e.g., transistors, resistors, capacitors, inductors, and so forth), integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate array (FPGA), logic gates, registers, semiconductor device, chips, microchips, chip sets, and so forth. Examples of software may include software components, programs, applications, computer programs, application programs, system programs, machine programs, operating system software, middleware, firmware, software modules, routines, subroutines, functions, methods, procedures, software interfaces, application program interfaces (API), instruction sets, computing code, computer code, code segments, computer code segments, words, values, symbols, or any combination thereof. Determining whether an embodiment is implemented using hardware elements and/or software elements may vary in accordance with any number of factors, such as desired computational rate, power levels, heat tolerances, processing cycle budget, input data rates, output data rates, memory resources, data bus speeds and other design or performance constraints.

One or more aspects of at least one embodiment may be implemented by representative instructions stored on a machine-readable medium which represents various logic within the processor, which when read by a machine causes the machine to fabricate logic to perform the techniques described herein. Such representations, known as “IP cores” may be stored on a tangible, machine readable medium and supplied to various customers or manufacturing facilities to load into the fabrication machines that actually make the logic or processor. Some embodiments may be implemented, for example, using a machine-readable medium or article which may store an instruction or a set of instructions that, if executed by a machine, may cause the machine to perform a method and/or operations in accordance with the embodiments. Such a machine may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. The machine-readable medium or article may include, for example, any suitable type of memory unit, memory device, memory article, memory medium, storage device, storage article, storage medium and/or storage unit, for example, memory, removable or non-removable media, erasable or non-erasable media, writeable or re-writeable media, digital or analog media, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW), optical disk, magnetic media, magneto-optical media, removable memory cards or disks, various types of Digital Versatile Disk (DVD), a tape, a cassette, or the like. The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, and the like, implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language.

Numerous specific details have been set forth herein to provide a thorough understanding of the embodiments. It will be understood by those skilled in the art, however, that the embodiments may be practiced without these specific details. In other instances, well-known operations, components, and circuits have not been described in detail so as not to obscure the embodiments. It can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments.

Some embodiments may be described using the expression “coupled” and “connected” along with their derivatives. These terms are not intended as synonyms for each other. For example, some embodiments may be described using the terms “connected” and/or “coupled” to indicate that two or more elements are in direct physical or electrical contact with each other. The term “coupled,” however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other.

Unless specifically stated otherwise, it may be appreciated that terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulates and/or transforms data represented as physical quantities (e.g., electronic) within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices. The embodiments are not limited in this context.

It should be noted that the methods described herein do not have to be executed in the order described, or in any particular order. Moreover, various activities described with respect to the methods identified herein can be executed in serial or parallel fashion.

Although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. It is to be understood that the above description has been made in an illustrative fashion, and not a restrictive one. Combinations of the above embodiments, and other embodiments not specifically described herein will be apparent to those of skill in the art upon reviewing the above description. Thus, the scope of various embodiments includes any other applications in which the above compositions, structures, and methods are used.

It is emphasized that the Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate preferred embodiment. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively. Moreover, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. 

The invention claimed is:
 1. A non-transitory, machine-readable medium having stored thereon instructions for performing a method comprising machine executable code which when executed by at least one machine, causes the machine to: receive an advertisement of a set of paths for accessing a logical storage volume, wherein the logical storage volume corresponds to a physical storage location and wherein each path of the set of paths includes a route through a port on an associated node; determine whether the set of paths comprises an optimized path based on a location of the associated node with respect to the physical storage location; and when the set of paths does not comprise an optimized path, send a first instruction to update a reporting nodes parameter for the logical storage volume to identify an owner node for the logical storage volume and a corresponding partner node.
 2. The non-transitory, machine-readable medium of claim 1, comprising machine executable code that, in response to being executed by the machine, cause the machine to perform a scan to discover one or more newly added paths corresponding to the current owner node.
 3. The non-transitory, machine-readable medium of claim 2, comprising machine executable code that, in response to being executed by the machine, cause the machine to update a multi-path input/output (MPIO) stack based on the one or more newly added paths.
 4. The non-transitory, machine-readable medium of claim 1, comprising machine executable code that, in response to being executed by the machine, cause the machine to send a second instruction to update the reporting nodes parameter to remove a previous owner node for the logical storage volume and a corresponding previous partner node.
 5. The non-transitory, machine-readable medium of claim 1, comprising machine executable code that, in response to being executed by the machine, cause the machine to send the first instruction prior to a mobility event according to which the logical storage volume is relocated to the owner node.
 6. The non-transitory, machine-readable medium of claim 5, the first instruction explicitly naming the owner node and corresponding partner node.
 7. The non-transitory, machine-readable storage medium of claim 5, the first instruction naming a storage aggregate owned by the owner node.
 8. The non-transitory, machine-readable storage medium of claim 1, the first instruction comprising a command line interface (CLI) command or an application programming interface (API) instruction.
 9. A computing device, comprising: a memory containing machine readable medium comprising machine executable code having stored thereon instructions for performing a method of path optimization; a processor coupled to the memory, the processor configured to execute the machine executable code to cause the processor to: receive an advertisement of a set of paths for accessing a logical storage volume, wherein the logical storage volume corresponds to a physical storage location and wherein each path of the set of paths includes a route through a port on an associated node; determine whether the set of paths comprises an optimized path based on a location of the associated node with respect to the physical storage location; and when the set of paths does not comprise an optimized path, send a first instruction to update a reporting nodes parameter for the logical storage volume to identify an owner node for the logical storage volume and a corresponding partner node.
 10. The computing device of claim 9, wherein the processor is further configured to execute the machine executable code to cause the processor to: perform a scan to discover one or more newly added paths corresponding to the current owner node.
 11. The computing device of claim 10, wherein the processor is further configured to execute the machine executable code to cause the processor to update a multi-path input/output (MPIO) stack based on the one or more newly added paths.
 12. The computing device of claim 9, wherein the processor is further configured to execute the machine executable code to cause the processor to send a second instruction to update the reporting nodes parameter to remove a previous owner node for the logical storage volume and a corresponding previous partner node.
 13. The computing device of claim 9, wherein the processor is further configured to execute the machine executable code to cause the processor to send the first instruction prior to a mobility event according to which the logical storage volume is relocated to the owner node.
 14. The computing device of claim 9, the first instruction comprising a command line interface (CLI) command or an application programming interface (API) instruction.
 15. A method, comprising: receiving an advertisement of a set of paths for accessing a logical storage volume, wherein the logical storage volume corresponds to a physical storage location and wherein each path of the set of paths includes a route through a port on an associated node; determining, by a processor circuit, whether the set of paths comprises an optimized path based on a location of the associated node with respect to the physical storage location; and when the set of paths does not comprise an optimized path, sending a first instruction to update a reporting nodes parameter for the logical storage volume to identify an owner node for the logical storage volume and a corresponding partner node.
 16. The method of claim 15, comprising performing a scan to discover one or more newly added paths corresponding to the current owner node.
 17. The method of claim 16, comprising updating a multi-path input/output (MPIO) stack based on the one or more newly added paths.
 18. The method of claim 15, comprising sending a second instruction to update the reporting nodes parameter to remove a previous owner node for the logical storage volume and a corresponding previous partner node.
 19. The method of claim 15, comprising sending the first instruction prior to a mobility event according to which the logical storage volume is relocated to the owner node.
 20. The method of claim 15, the first instruction comprising a command line interface (CLI) command or an application programming interface (API) instruction. 